Test class for Apex Plug-In that calculates monthly payment (for Force.com Cloud Flow Designer Workbook)

MortgageCalculatorTest.txt

@isTest
global class MortgageCalculatorTest {
    public static testmethod void testAll()
    {
        MortgageCalculator plugin = new MortgageCalculator();
        Map<String,Object> inputParams = new Map<String,Object>();
        Double amount = 500000;
        Double term = 360;
        Double rate = 5;
        inputParams.put('Amount', amount);
        inputParams.put('Term', term);
        inputParams.put('Rate', rate);
        Process.PluginRequest request = new Process.PluginRequest(inputParams);
        Process.PluginResult aresult = Plugin.invoke(request);
        Double monthlyAmount = (Double) aresult.outputParameters.get('MonthlyPayment');
        System.assertEquals(Math.roundToLong(monthlyAmount),2684);
        Process.PluginDescribeResult describe = plugin.describe();
        System.assertEquals(describe.InputParameters.size(), 3);
        System.assertEquals(describe.InputParameters[0].name, 'Amount');
        System.assertEquals(describe.InputParameters[1].name, 'Term');
        System.assertEquals(describe.InputParameters[2].name, 'Rate');
        System.assertEquals(describe.OutputParameters.size(), 1);
        System.assertEquals(describe.OutputParameters[0].name, 'MonthlyPayment');
    }
}